Impact of “3414” fertilization on the yield and quality of greenhouse tomatoes

Abstract This study aimed to explore the effects of different nitrogen, phosphorus, and potassium ratios on the yield and nutritional quality of greenhouse tomatoes under a water and fertilizer integration model. Greenhouse tomatoes were used as the research object, and the “3414” fertilizer trial design was employed to assess tomato growth, yield, quality, and soil indicators across various treatment combinations. The goal was to determine the optimal fertilization scheme and recommend appropriate fertilizer quantities for tomato cultivation and production. The results revealed that different fertilizer ratios significantly affected both the quality and yield of tomatoes. Overall, the tomato yield tended to increase with higher fertilization amounts, with potassium exhibiting the most pronounced effect on yield increase, followed by phosphorus and nitrogen. The comprehensive analysis of principal components indicated that the N2P2K1 treatment yielded the highest nutritional quality and yield. Therefore, the best fertilization combination identified in this study consisted of nitrogen fertilizer at 197.28 kg hm−2, phosphorus fertilizer at 88.75 kg hm−2, and potassium fertilizer at 229.80 kg hm−2. These findings provided the scientific basis for optimizing fertilization practices in greenhouse tomato cultivation and production in the Jilin Province.


Introduction
Tomato (Lycopersicon esculentum) is an annual or perennial herbaceous plant belonging to the Solanaceae family.It is extensively cultivated in both northern and southern regions of China.It ranks among the most commonly grown greenhouse vegetables globally [1].Tomatoes are characterized by their vibrant colors, distinctive flavor, and high contents of nutrients, such as carotene, lycopene, and vitamins C and B.Besides their nutritional value, tomatoes possess high medicinal value, aiding digestion, detoxification, and preventing cardiovascular diseases [2,3].Given their high water and nutrient requirements, greenhouse tomato cultivation has gained widespread adoption, ensuring a steady supply of fresh produce.Integrated water and fertilizer technologies represent advanced fertilizer management techniques that enhance water and nutrient utilization efficiency, ultimately maximizing economic returns [4,5].Fertilization is a pivotal technique in tomato cultivation and production, playing a crucial role in improving soil fertility, facilitating tomato growth and development, and increasing yield and quality [6,7].However, the indiscriminate use of fertilizers can have negative consequences [8,9].Therefore, appropriate fertilization practices are essential for promoting agricultural productivity and achieving superior crop quality and yield.
Nitrogen, phosphorus, and potassium are essential elements for the normal growth and development of plants.Improper combinations of these three elements can lead to crop nutrient imbalances, increased fruit nitrate content, decreased quality, low yield, and imbalanced soil nutrient supply [10][11][12].Studies on the impact of nitrogen, phosphorus, and potassium fertilizers on tomatoes exist [13,14].However, previous studies have examined only a limited range of nitrogen, phosphorus, and potassium ratios, neglecting the interactive effects and influence of multiple levels.In addition, the variations in soil fertility, crop residues, and cultivated varieties can alter the optimal fertilization scheme for crops.The "3414" experimental design plays a significant role in national soil testing and formula fertilization efforts.It can determine the appropriate application amounts of nitrogen, phosphorus, and potassium based on soil fertility, crop fertilization requirements, and fertilizer response functions.This experimental plan is extensively used for studying fertilizer efficiency both domestically and internationally [15].The high-quality and efficient cultivation of greenhouse tomatoes in the Jilin Province holds significant economic importance for greenhouse film industries.This study was based on the integrated water and fertilizer technology for tomatoes and aimed to strengthen the research on rational fertilization techniques for greenhouse tomatoes.Employing the "3414" experimental design, we investigated the combined effects of nitrogen, phosphorus, and potassium application on the growth and quality of tomatoes in greenhouse facilities.The goal was to determine the optimal fertilization ratio to improve the tomato yield and quality, providing a theoretical basis for scientifically sound fertilization practices in high-quality tomato production and cultivation.

Study location and materials
The study was conducted at the teaching and research base of Jilin Agricultural University, situated at 125°41′ East longitude and 43°82′ North latitude.The area experiences a temperate continental semi-humid monsoon climate characterized by an average annual sunshine duration of 2544.8 h, an effective accumulated temperature of 2,850℃, a frost-free period of 145 days, an average annual temperature of 5.8℃, and an average annual precipitation of 558 mm.The soil used in the study was black soil, possessing the following basic physical and chemical properties: bulk density of 0.97 g cm −3 , total porosity of 59.66%, soil pH of 6.7, organic matter content of 34.39 g kg −1 , alkali nitrogen content of 161 mg kg −1 , available phosphorus content of 50.91 mg kg −1 , and available potassium content of 190.04 mg kg −1 .The tomato variety selected for the experiment was "Shidun 197," characterized by an indeterminate growth type with medium early maturity.The fertilizers used included urea (N: 46%), calcium superphosphate (P 2 O 5 : 12%), and potassium sulfate (K 2 O: 50%).

Study design
The tomato seeds were sown in March 2023, using pot planting experiments, and later transplanted on May 6, with 5 plants per treatment and 3 repetitions, totaling 210 plants.During the growth period, single-stem pruning was conducted, with five fruit clusters retained per plant.The harvesting started on July 15, 2023.The study employed the "3414" fertilizer trial plan, with nitrogen, phosphorus, and potassium serving as the 3 elements, each at 0, 1, 2, and 3 levels, resulting in 14 treatments.The experimental factors and levels are detailed in Table 1, and the experimental treatments and corresponding fertilization amounts are provided in Table 2. Fertilization started 10 days after planting, facilitated by a fertigation system for integrated irrigation and fertilization management.The fertilizer application adhered to the critical growth periods of tomatoes, with 15% of the total supply administered during the plantingto-flowering phase and 85% during the fruiting period.Additionally, the water supply was adjusted following tomato growth and prevailing weather conditions.

Measurement indicators and methods
The soil pH value was measured using the potentiometric method with a pHS-3E acidity meter (Shanghai Yoke Instrument Co., Ltd.).The electrical conductivity (EC) value was determined using the conductivity method with a DDS-11A electromagnetic conductivity meter (Shanghai Yoke Instrument Co., Ltd.).The alkali nitrogen content was determined using the NaOH alkali diffusion-absorption method.The available phosphorus content was determined using the NaHCO 3 extraction-molybdenum antimony colorimetric method.The available potassium content was determined using the NH 4 OAC extraction-flame photometry method [16].
The plant height was measured using a tape measure from the first leaf to the top growth point.The stem thickness was measured using a Vernier caliper at the midpoint between the first and second leaves.The tomato leaf area was obtained using the weighing method.Starting from the tomato harvest period, the yield for each experimental treatment was determined, and the yield per plant was recorded.
The soluble sugar content of tomato fruit was measured using the anthrone method.The soluble protein content was determined using the Coomassie brilliant blue G-250 staining method.The soluble solid contents were measured using a refractometer.The organic acid contents were determined using acid-base titration.The vitamin C content was determined using the molybdenum blue colorimetric method.The nitrate and lycopene contents were determined using ultraviolet spectrophotometry [17,18].

Statistical analysis
The experimental data were organized using Microsoft Excel 2021.Significance testing and principal component analysis were conducted using SPSS version 26 statistical analysis software.

Results
3.1 Effects of different nitrogen, phosphorus, and potassium ratios on the physical and chemical properties of soil for tomato cultivation The physical and chemical properties of the experimental soil under different fertilization treatments are presented in Table 3.The soil pH under the CK treatment was the highest (7.39), significantly surpassing that under other treatments.Conversely, the pH of the N 3 P 2 K 2 treatment was the lowest (6.32), indicating that the high-nitrogen fertilizer treatment resulted in decreased pH levels.This decline in soil pH could be attributed to long-term excessive fertilization.The EC value was the highest under the N 3 P 2 K 2 treatment (1145.33 μs cm −1 ), significantly exceeding that under other treatments.Conversely, the N 0 P 2 K 2 treatment exhibited the lowest EC value (317.23 μs cm −1 ), indicating that the application of higher amounts of fertilizer led to increased soil EC values.This elevation implied a higher salt content in the soil, potentially impeding plant growth and development.The highest alkali nitrogen content was recorded under the N 3 P 2 K 2 treatment (172.67 mg kg −1 ), followed by that under the N 2 P 2 K 3 and N 2 P 2 K 2 treatments (169.17 and 166.83 mg kg −1 ), respectively.The lowest alkali nitrogen content was recorded under the CK treatment (114.33 mg kg −1 ), indicating that applying nitrogen fertilizers increases the alkali nitrogen content in the soil.The available phosphorus content was the highest under the N 2 P 2 K 3 treatment (54.13 mg kg −1 ), followed by that under the N 2 P 2 K 3 treatment (52.31 mg kg −1 ), with no significant difference compared with that under N 1 P 2 K 1 , N 3 P 2 K 2 , and N 1 P 1 K 2 treatments but with significant difference compared with that under other treatments.Conversely, the available phosphorus content was the highest under the CK treatment (35.82 mg kg −1 ), indicating that soil without phosphorus fertilizers had a lower available phosphorus content.Moreover, the available potassium content was the highest under the N 2 P 2 K 3 treatment (230.23 mg kg −1 ), which was significantly higher than that under other treatments.Conversely, the available potassium content was the lowest under the N 2 P 2 K 0 treatment (158.40 mg kg −1 ), indicating that applying potassium fertilizers significantly increases the available potassium content in the soil.

Effects of different nitrogen, phosphorus, and potassium ratios on the growth indicators of tomato plants
As depicted in Table 4, the tallest plant was observed under the N 0 P 2 K 2 treatment (133.23 cm), followed by 132.10 cm under the CK treatment.Conversely, the plant heights under N 2 P 2 K 2 , N 1 P 2 K 1 , N 1 P 2 K 2 , and N 1 P 1 K 2 treatments were significantly lower than those under N 0 P 2 K 2 and CK treatments.The plants were the shortest under the N 1 P 1 K 2 treatment (94.30 cm).The CK treatment, with no fertilizer, led to better plant growth, indicating that the soil fertilizers used during the experiment ensured the normal growth of tomatoes in the early stage.Additionally, using equivalent nitrogen fertilizer amounts, the combined application of phosphorus and potassium fertilizers positively impacted the plant growth.
The stem thickness was the highest under the N 2 P 1 K 1 treatment (12.13 mm), significantly differing from that under N 2 P 2 K 3 , N 1 P 2 K 2 , N 1 P 2 K 1 , N 2 P 2 K 2 , and N 2 P 3 K 2 treatments.This represented a 5.39% increase compared with the CK treatment.Conversely, the stem thickness was the lowest under the N 2 P 3 K 2 treatment (9.24 mm), significantly differing from that under N 3 P 2 K 2 , N 2 P 1 K 2 , CK, N 2 P 2 K 1 , N 0 P 2 K 2 , and N 2 P 1 K 1 treatments.These findings suggested that the application of appropriate phosphorus and potassium amounts could enhance tomato stem thickening within a certain range.
The leaf area was the largest under the N 2 P 1 K 1 treatment (79.72 cm²), followed by 77.04 and 76.59 cm² under the N 2 P 2 K 3 and N 2 P 1 K 1 treatments, respectively.These represented increases of 10.61, 6.70, and 6.27%, respectively, compared with the CK treatment.Conversely, the leaf area was the smallest under the N 1 P 2 K 2 treatment (63.53 cm).However, the leaf area under the N 2 P 2 K 3 and N 2 P 2 K 0 treatments did not significantly differ, with the former showing an 18.67% increase, indicating that potassium fertilizer application at the same nitrogen and phosphorus levels was beneficial for increasing tomato leaf area.
Dry matter accumulation in tomato plants was the highest under the N 2 P 1 K 1 treatment (310.29 g/plant), followed by 298.89 g/plant under the N 2 P 2 K 1 treatment.Both values significantly exceeded those observed under other treatments, with increases of 59.56 and 53.68%, respectively, compared with that under the CK treatment, which had the lowest accumulation at 194.47 g/plant.Additionally, dry matter accumulation in tomatoes exhibited a trend of initially increasing and then decreasing with an increase in the amounts of nitrogen, phosphorus, and potassium fertilizers.

Effects of different nitrogen, phosphorus, and potassium ratios on the tomato yield
As depicted in Table 5, the average weight of a single tomato fruit was the highest under the N 2 P 1 K 1 treatment (167.42 g), followed by 161.23 g under the N 2 P 2 K 1 treatment.It was significantly higher than that under the CK, N 2 P 2 K 0 , and N 1 P 2 K 1 treatments, representing increases by 26.15 and 21.49%, respectively, compared with that under the CK treatment.The total yield of tomatoes under different fertilization treatments indicated that the yield was higher under fertilizer treatments than under non-fertilizer treatments.Among these, the highest yield was observed under the N 2 P 1 K 1 treatment (106803.63 kg hm −2 ), followed by 104139.00 and 102934.88kg hm −2 under the N 2 P 2 K 2 and N 2 P 2 K 1 treatments, respectively.These represented increases of 40.15, 36.66, and 35.08% compared with the non-fertilizer treatment.The interaction effect of nitrogen, phosphorus, and potassium was the strongest, followed by the interaction effects of phosphorus and potassium, and those of nitrogen and potassium, with yield increases of 20.70 and 16.51%, respectively (Table 6).The interaction effect of nitrogen and phosphorus was the weakest, with a yield increase of only 3.43%.The relative yield in the nitrogen-deficient areas was 88.32%, with a nitrogen dependence of 11.68%.The relative yield in phosphorus-deficient areas was 85.26%, with a phosphorus dependence of 14.74%.The relative yield in potassium-deficient areas was 75.68%, with a potassium dependence of 24.32%.Therefore, the order of dependence was as follows: nitrogen dependence < phosphorus dependence < potassium dependence, indicating that potassium fertilizer had a significant impact in terms of increasing yield compared with phosphorus fertilizer, whereas the effect of nitrogen fertilizer was smaller.Additionally, applying nitrogen, phosphorus, and potassium together was more conducive to increasing tomato yield.

Effects of different nitrogen, phosphorus, and potassium ratios on the quality of tomato fruits
As depicted in Table 7, different ratios of nitrogen, phosphorus, and potassium fertilizer treatments significantly impacted the quality of tomato fruits.Among these, the N 2 P 1 K 1 treatment exhibited the highest soluble protein content (3.86 mg g −1 ), followed by 3.54 mg g −1 under the N 2 P 2 K 1 treatment.The soluble protein content under the N 2 P 1 K 1 and N 2 P 2 K 1 treatments was significantly higher than that under the no-fertilizer treatment, increasing by 69.30 and 55.26%, respectively.Significant differences were found in the soluble sugar content of tomato fruits under different treatments.At the same nitrogen and phosphorus levels, the soluble sugar content increased first and then decreased with increasing potassium fertilizer application.Among these, the N 2 P 2 K 1 treatment exhibited the highest soluble sugar content (4.36%), followed by the N 2 P 2 K 2 and N 2 P 2 K 0 treatments, which were significantly higher than that under the CK treatment, with increases of 42.95, 22.62, and 18.69%, respectively.Conversely, the soluble sugar content was the lowest under the N 2 P 1 K 2 treatment (1.79%).
The N 2 P 2 K 1 treatment yielded the highest soluble solid content in tomato fruits, exhibiting significant differences compared with the N 1 P 1 K 2 and CK treatments, with increases of 10.31 and 9.59%, respectively.Conversely, the lowest soluble solid content was recorded under the N 2 P 1 K 2 treatment (3.73%), representing a decrease of 10.55% compared with that under the CK treatment.In addition, no significant differences were observed in the contents under the CK and other treatments.
The highest vitamin C content in tomato fruits was recorded under the N 2 P 0 K 2 treatment (32.26 mg 100 g −1 ), compared with that under the CK treatment, with a 24.90% increase.Vitamin C content under the N 2 P 2 K 0 , N 2 P 2 K 1 , N 2 P 2 K 2 , and N 2 P 2 K 3 treatments was 28.15, 29.52, 31.30, and 30.07 mg 100 g −1 , respectively.The vitamin C content in tomatoes increased first and then decreased with the increase in potassium fertilizer application at the same nitrogen and phosphorus fertilizer levels.This suggested that, although increasing the potassium fertilizer amount increased the vitamin C content in fruits, excessive application should be avoided.
The organic acid content of tomatoes treated with N 1 P 2 K 2 was the highest (0.47%), whereas the content of tomatoes treated with CK was the lowest (0.23%).A significant difference in content was observed between these two treatments.In addition, no significant difference was observed in the content between the N 1 P 2 K 2 treatment and other treatments.
The nitrate content in tomato fruits was the highest under the N 2 P 1 K 2 treatment (171.78 mg kg −1 ) compared with that under the CK treatment, with an increase of 38.30%.Conversely, the content was the lowest under the N 0 P 2 K 2 treatment (110.09mg kg −1 ), marking a decrease of 11.37% compared with that under the CK treatment.Under N 1 P 2 K 2 , N 2 P 2 K 2 , and N 3 P 2 K 2 treatments, the nitrate content was 165.88, 118.64, and 148.65 mg kg −1 , respectively, demonstrating increases of 50.68, 7.77, and 35.03%, respectively, compared with that under the N 0 P 2 K 2 treatment, implying that additional nitrogen fertilizer application increased the nitrate content.
The combined application of nitrogen, phosphorus, and potassium fertilizers increased the lycopene content in fruits.The highest content was observed under the N 2 P 2 K 1 treatment (22.44 mg kg −1 ), significantly surpassing that under other treatments.This represented an 81.70% increase compared with that under the non-fertilizer treatment.Moreover, at the same nitrogen and potassium fertilizer levels, the lycopene content increased with the increase in phosphorus fertilizer amount, peaking at 17.08 mg kg −1 under the N 2 P 3 K 2 treatment, marking a 38.30% increase compared with that under the non-fertilizer treatment.

Fertilizer model and comprehensive evaluation analysis
3.5.1 Comprehensive analysis of the synergistic effects of nitrogen, phosphorus, and potassium fertilizers Based on the "3414" field fertilizer experimental design, regression analysis was conducted on the interaction effects between nitrogen, phosphorus, and potassium using the fertilization and yield data from the 14 treatment groups.Then, a ternary fertilizer effect function equation was fitted.
According to the ternary fertilizer effect equation, the maximum application amount of nitrogen, phosphorus, and potassium was 140.49, 73.33, and 472.26 kg hm −2 , respectively.The calculated theoretical maximum yield was 102118.84kg hm −2 .When the levels of nitrogen, phosphorus, and potassium were all 0, the constant term (theoretical blank area yield) was 75411.899kg hm −2 , which closely matched the actual yield of 76204.00kg hm −2 .This indicated that the fitting of the fertilizer effect function equation was relatively consistent with production reality, providing an objective reflection of the impact of combined fertilizer application on yield and fertilizer effects.

Comprehensive evaluation and analysis of tomato quality and yield
A relatively optimal fertilizer ratio was selected using principal component analysis for comprehensive analysis.The soluble sugar content, soluble protein content, soluble solid content, organic acid content, sugar acid ratio, vitamin C content, nitrate content, tomato lycopene content, and total yield of 14 tomato treatment groups were comprehensively evaluated to select a fertilizer ratio that would produce high-quality and high-yield tomatoes.First, the original data were standardized, and then the standardized values were analyzed to obtain the eigenvalues and contribution rates of the correlation matrix (Table 8).According to the principle that eigenvalues greater than 1 can be extracted, four principal components were identified with eigenvalues of 3.54, 1.85, 1.33, and 1.15 and variance contribution rates of 39.33, 20.53, 14.76, and 12.81%, respectively.F 1 -F 4 represent the scores of the four principal components, and the score coefficient equations for the four principal components are as follows:

= + + +
The nutritional quality and yield of 14 tomato treatments were comprehensively evaluated based on the F value.As shown in Table 9, the treatment with the highest comprehensive score was N 2 P 2 K 1 , followed by N 2 P 2 K 2 .

Discussion
Soil serves as the essential substrate for crop survival, with nitrogen, phosphorus, and potassium elements providing the nutrients necessary for plant growth and development.The physical and chemical properties of soil serve as crucial indicators for evaluating soil quality, directly reflecting its vitality and the status of nutrient supply.Excessive fertilization can decrease soil pH and increase EC values under experimental conditions, leading to soil acidification and increased soil salinity.This situation is not conducive to plant growth and development.The contents of soil alkali-hydrolyzable nitrogen, available phosphorus, and available potassium increase with the application of increased amounts of nitrogen, phosphorus, and potassium fertilizers.This may be attributed to the incomplete absorption of fertilizers by plants.This not only hampers the tomato fruit yield and quality but also contributes to soil salinization and fertilizer wastage, consistent with the findings of previous studies [19].
Nitrogen, phosphorus, and potassium are essential for plant growth.Plant height and stem thickness serve as crucial indicators of tomato nutrition and growth.In this study, plants treated with N 0 P 2 K 2 exhibited the largest plant height, whereas those treated with N 2 P 0 K 2 had the largest leaf area.This suggested that the coordination between phosphorus and potassium led to taller plants without nitrogen fertilizer, and the coordination between nitrogen and potassium resulted in larger leaf areas without phosphorus fertilizer.This could be due to sufficient nitrogen in the soil, supporting the early growth of tomato plants.Plants treated with N 2 P 1 K 1 displayed the largest stem thickness, whereas those treated with N 2 P 3 K 2 had the smallest stem thickness.This indicated that excessive phosphorus fertilizer might not be conducive to the increase in stem thickness of tomatoes.Within a certain range, the application of nitrogen, phosphorus, and potassium fertilizers could promote plant growth.However, excessive amounts of any nutrient led to nutrient imbalance, resulting in no growth-promoting effect or even growth inhibition [20].Studies showed that an appropriate combination of nitrogen, phosphorus, and potassium fertilizers enhanced dry matter accumulation in potato tubers [21].Similarly, this study revealed that plants treated with N 2 P 1 K 1 exhibited the highest dry matter accumulation, and the interaction between nitrogen, phosphorus, and potassium significantly affected dry matter accumulation in tomatoes.
The soluble protein, soluble sugar, soluble solids, organic acids, vitamin C, and lycopene in tomato fruits are vital quality indicators that directly influence the nutritional value, taste, and commercial value of tomatoes [22,23].The quality of tomato fruits is influenced by various ratios of nitrogen, phosphorus, and potassium, and an optimal ratio can significantly improve it [24][25][26].This study showed that an appropriate combination of nitrogen, phosphorus, and potassium effectively improved the nutritional quality of tomato fruits.Additionally, potassium fertilizer application increased the contents of soluble sugar, soluble solids, soluble protein, and lycopene in tomato fruits to varying degrees.These contents first increased and then decreased with the increase in potassium application, which was consistent with previous research findings [27].Additionally, excessive use of nitrogen fertilizer and prolonged application significantly elevated the nitrate content in tomato fruits, exceeding the standard limit and posing health risks to consumers.
Fertilization plays a crucial role in boosting the tomato yield.Proper fertilization practices are essential for vegetable crops to achieve high yields and maintain quality standards [28].In the experimental setup, the N 2 P 1 K 1 treatment led to the highest yield, with the amount of phosphorus and potassium fertilizers being below the optimal level.The impact of nitrogen, phosphorus, and potassium fertilizers on the tomato yield follows the following order: nitrogen < phosphorus < potassium, suggesting that increasing potassium fertilizer application could effectively increase the tomato yield.
Some studies showed that the pumpkin yield increased first and then decreased with the increase in the amount of nitrogen, phosphorus, and potassium fertilizers, with recommended dosages of 390.5 kg for nitrogen fertilizer, 213.8 kg for phosphorus fertilizer, and 371.3 kg for potassium fertilizer per hectare for "Jianbao" pumpkin [29].Similarly, studies on Angelica sinensis suggested the optimal fertilizer application amounts of nitrogen, phosphorus, and potassium fertilizers to be 81.15,80.67, and 29.78 kg hm −2 , respectively, resulting in a maximum seedling transplanting yield of 1932.52 kg hm −2 [15].The ternary quadratic fertilizer function equation fitted in this "3414" fertilizer experiment expressed the relationship between the total tomato yield and the application of nitrogen, phosphorus, and potassium fertilizers.Based on this equation, the calculated application rate was 140.49kg hm −2 for nitrogen fertilizer, 73.33 kg hm −2 for phosphorus fertilizer, and 472.26 kg hm −2 for potassium fertilizer, with a fertilizer ratio of 1:0.50:3.05.The highest expected yield was projected to be 102118.84kg hm −2 .

Conclusions
Fertilization significantly impacts both the quality and yield of tomatoes.Applying nitrogen, phosphorus, and potassium fertilizers in various proportions can enhance soil fertility, stimulate tomato plant growth, and augment both the quality and yield of tomatoes.A comprehensive analysis revealed that the most suitable fertilization treatment under the experimental environment and planting conditions was N 2 P 2 K 1 .Therefore, N 2 P 2 K 1 was recommended as the optimal fertilization formula for producing highquality and high-yield tomatoes in the experimental area, with the amount of nitrogen fertilizer being 197.28 kg hm −2 , phosphorus fertilizer being 88.75 kg hm −2 , and potassium fertilizer being 229.80 kg hm −2 .This approach was conducive to achieving efficient and high-quality tomato production.However, the yield and quality of tomatoes were affected by various factors besides fertilization, necessitating further studies on other aspects.

Table 2 :
Experimental treatments and fertilizer application amount

Table 3 :
Effects of different nitrogen, phosphorus, and potassium ratios on the physicochemical properties of soil for tomato cultivation Note: The data in the table represent mean ± standard deviation.Different letters following the numbers in the same column indicate significant differences at the 0.05 level.

Table 4 :
Effects of different nitrogen, phosphorus, and potassium ratios on tomato growth indexes Note: The data in the table represent mean ± standard deviation.Different letters following the numbers in the same column indicate significant differences at the 0.05 level.

Table 5 :
Effects of different nitrogen, phosphorus, and potassium ratios on the tomato yield The data in the table represent mean ± standard deviation.Different letters following the numbers in the same column indicate significant differences at the 0.05 level.

Table 6 :
Effects of nitrogen, phosphorus, and potassium interaction on the tomato yield

Table 7 :
Effects of different nitrogen, phosphorus, and potassium ratios on tomato fruit quality The data in the table represent mean ± standard deviation.Different letters following the numbers in the same column indicate significant differences at the 0.05 level.
The comprehensive score for each treatment was calculated based on the values of F 1 , F 2 , F 3 , and F 4 , as well as the weights of the contributions of each principal component.

Table 8 :
Eigenvalues and variance contribution rates of principal component analysis

Table 9 :
Comprehensive score table of tomato nutrition quality and yield with different NPK ratios